Resin-extended elastomer

Abstract

The invention relates to a resin-extended elastomer, the elastomer of which is a synthetic diene elastomer having a number-average molar mass greater than or equal to 200,000 g / mol and the resin of which is a plasticizing hydrocarbon resin. The invention also relates to a method for obtaining such a resin-extended elastomer, and also to compositions, finished products for tyres and tyres containing same.

Description

[0001] The present invention relates to a resin-extended elastomer, to a process for obtaining it and to rubber compositions containing it. These rubber compositions can be used in particular for the manufacture of tires.

[0002] Since fuel economy and the need to preserve the environment have become a priority, it has become desirable to produce tires with reduced rolling resistance without compromising their other properties such as high grip on both dry and wet roads.

[0003] One way of achieving this compromise of properties, in particular from the point of view of rolling resistance and grip on both dry and wet roads, consists of using a high level of plasticizers, in particular a high level of plasticizing resins, in low hysteretic rubber compositions having the characteristic of being reinforced by reinforcing inorganic fillers, such as highly dispersible silicas known as "HDS" (Highly Dispersible Silica), capable of competing from the point of view of reinforcing power with conventional tire-grade carbon blacks.

[0004] These compositions are prepared in the usual manner by incorporating all of their constituents into mixers. EP2423252 A1 describes in particular a rubber composition for tires comprising a synthetic polyisoprene extended by a thermoplastic hydrocarbon resin.

[0005] However, the incorporation of high levels of plasticizing resins during the manufacture of these compositions poses problems.

[0006] Indeed, this incorporation of high levels of plasticizing resins in a rubber composition results in an increase in the stickiness of the composition. This increase is so significant that the rubber composition sticks to the mixer rotors or to various other metal elements of the mixing line, preventing the mixer from functioning properly. This can result in a loss of material, i.e. only part of the material introduced into the mixer comes out at its end. In addition, very often, it is necessary to stop the mixer to remove the composition stuck to the metal parts. Stopping the mixer for manual cleaning is very penalizing for manufacturers since it causes a drop in productivity. Compositions with a high level of plasticizing resins are therefore differently processable in the usual tools for manufacturing rubber compositions such as internal mixers.

[0007] The technical problem that the invention aims to solve is to improve the processability of rubber compositions having high resin levels.

[0008] This aim is achieved in that the applicant has just surprisingly discovered during its research that the use of a specific compound gives the compositions containing it a reduction in their stickiness. This specific compound improves the processability of such rubber compositions.

[0009] Thus, the subject of the invention is a resin-extended elastomer, the elastomer of which is a synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol and the resin of which is a plasticizing hydrocarbon resin and the content of plasticizing hydrocarbon resin in a range from 30 to 100 phr, the resin-extended elastomer being obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon resin in the liquid state and the resin-extended elastomer having a Mooney viscosity index greater than or equal to 40 UM.

[0010] According to a preferred embodiment, the synthetic diene elastomer comprises at least one conjugated diene monomer having from 4 to 12 carbon atoms.

[0011] According to a preferred embodiment, the conjugated diene monomer having 4 to 12 carbon atoms is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C 1 -C 5 alkyl)-1,3-butadienes, 1,3-pentadiene, 2,4-hexadiene and mixtures of these monomers.

[0012] According to a preferred embodiment, the conjugated diene monomer having 4 to 12 carbon atoms is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene and mixtures of these monomers.

[0013] According to a preferred embodiment, the synthetic diene elastomer further comprises at least one vinylaromatic monomer having from 8 to 20 carbon atoms.

[0014] According to a preferred embodiment, the vinylaromatic monomer having from 8 to 20 carbon atoms is selected from the group consisting of styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene and mixtures of these monomers.

[0015] According to a preferred embodiment, the vinyl aromatic monomer having from 8 to 20 carbon atoms is styrene and the conjugated diene monomer having 4 to 12 carbon atoms is 1,3-butadiene.

[0016] According to a preferred embodiment, the synthetic diene elastomer is functionalized by a function selected from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane, carboxylic groups, polyether groups, epoxide groups and mixtures thereof.

[0017] According to a preferred embodiment, the synthetic diene elastomer is obtained by solution polymerization, preferably by homogeneous solution polymerization.

[0018] According to a preferred embodiment, the plasticizing hydrocarbon resin has a number-average molar mass of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol.

[0019] According to a preferred embodiment, the plasticizing hydrocarbon resin is chosen from the group consisting of aliphatic resins, aromatic resins and mixtures of these resins.

[0020] According to a preferred embodiment, the plasticizing hydrocarbon resin is selected from the group consisting of cyclopentadiene homopolymer or copolymer resins, dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, mixtures of C5-cut homopolymer or copolymer resins and C9-cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins and mixtures of these resins.

[0021] The content of plasticizing hydrocarbon resin is in the range of 30 to 100 pce, preferably 30 to 80 pce.

[0022] Resin-extended elastomer is obtained by mixing synthetic diene elastomer in solution in an organic solvent and plasticizing hydrocarbon resin in liquid state.

[0023] Another object of the present invention relates to a process for obtaining said resin-extended elastomer, the process comprising at least: (a) a step of bringing at least one synthetic diene elastomer in solution in an organic solvent into contact with at least one plasticizing hydrocarbon resin, said synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol, (b) a mixing step to obtain a homogeneous solution of synthetic diene elastomer and plasticizing hydrocarbon resin, (c) a steam stripping step to recover a gaseous fraction enriched in organic solvent and an aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin; and (d) a step of recovering the resin-extended elastomer from the aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin.

[0024] According to a preferred embodiment, the production process further comprises between the step of removing the organic solvent (c) and the drying step (d) at least one step (c') of washing the aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin.

[0025] According to a preferred embodiment, the gaseous fraction enriched in organic solvent is recycled to step (a).

[0026] According to a preferred embodiment, the synthetic diene elastomer of step (a) is obtained either by dissolving said elastomer in the organic solvent or by polymerization in solution in the organic solvent of the corresponding monomers of said elastomer.

[0027] According to a preferred embodiment, during contact in step (a), the plasticizing hydrocarbon resin is in the liquid state.

[0028] According to a preferred embodiment, the plasticizing hydrocarbon resin in the liquid state is obtained by heating said resin to a temperature greater than or equal to its softening temperature.

[0029] According to a preferred embodiment, the plasticizing hydrocarbon resin in the liquid state is obtained by dissolving said resin in an organic solvent identical to or different from the organic solvent in which the synthetic diene elastomer is found.

[0030] According to a preferred embodiment, said synthetic diene elastomer has a glass transition temperature of less than or equal to -60°C, more preferably within a range from -110°C to -60°C, more preferably from -95°C to -65°C.

[0031] According to a preferred embodiment, the synthetic diene elastomer comprises at least one conjugated diene monomer having from 4 to 12 carbon atoms.

[0032] According to a preferred embodiment, the synthetic diene elastomer further comprises at least one vinylaromatic monomer having from 8 to 20 carbon atoms.

[0033] According to a preferred embodiment, the synthetic diene elastomer is functionalized by a function chosen from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane, carboxylic groups, polyether groups, epoxide groups and mixtures thereof.

[0034] According to a preferred embodiment, the plasticizing hydrocarbon resin has a number-average molar mass of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol.

[0035] According to a preferred embodiment, the plasticizing hydrocarbon resin has a glass transition temperature greater than or equal to 20°C, preferably greater than or equal to 30°C.

[0036] Another subject of the present invention relates to a resin-extended elastomer capable of being obtained by the process defined above.

[0037] The resin-extended elastomer has a Mooney viscosity index greater than or equal to 40 UM, preferably in the range of 50 to 75 UM.

[0038] Surprisingly, despite the high number-average molar mass of the resin-extended elastomer, it has good Mooney viscosity and can be used in rubber compositions.

[0039] Thus, another subject of the present invention relates to a composition based on at least one elastomer extended with resin as defined above or capable of being obtained according to the process described above and at least one reinforcing filler.

[0040] According to a preferred embodiment, the composition further comprises at least one chemical crosslinking system.

[0041] The rubber compositions containing a resin-extended elastomer according to the invention have the advantage, despite the presence of a high level of plasticizing resin, of having a lower adhesive capacity on the mixing tools than compositions containing the same level of plasticizing resin and an elastomer of the same microstructure, not extended with resin. The use of this resin-extended elastomer in rubber compositions allows a gain in productivity of the mixing line; the line stops for cleaning are more limited due to better processability of the rubber composition containing such a compound.

[0042] Another subject of the present invention relates to a semi-finished product for a tire comprising at least one resin-extended elastomer as defined above or capable of being obtained by the process described above.

[0043] Another subject of the present invention relates to a semi-finished product for a tire comprising at least one composition as defined above.

[0044] Another subject of the present invention relates to a tire comprising at least one resin-extended elastomer as defined above or capable of being obtained by the process described above.

[0045] Another subject of the present invention relates to a tire comprising at least one composition as defined above. 1 - MEASUREMENT METHODS USED 1.1 Measurement of number-average molar masses (Mn), weight-average molar masses (Mw) and polydispersity index for resin-extended or non-resin-extended elastomers

[0046] Size exclusion chromatography (SEC) is used. SEC separates macromolecules in solution according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the largest being eluted first.

[0047] Although not an absolute method, SEC allows us to understand the distribution of molar masses of an elastomer. From commercial standard products, the different number-average (Mn) and weight-average (Mw) molar masses can be determined and the polydispersity index (Ip = Mw / Mn) calculated via a so-called MOORE calibration. Preparation of the elastomer sample to be tested:

[0048] There is no special treatment of the elastomer sample before analysis. It is simply solubilized at a concentration of approximately 1 g / l, in chloroform or in the following mixture: tetrahydrofuran + 1% vol. of diisopropylamine + 1% vol. of triethylamine + 1% vol. of distilled water (% vol. =% volume). Then, the solution is filtered through a 0.45 µm porosity filter before injection. SEC Analysis:

[0049] The apparatus used is a "WATERS alliance" chromatograph. The elution solvent is the following mixture: tetrahydrofuran + 1% vol. diisopropylamine + 1% vol. triethylamine or chloroform depending on the solvent used for dissolving the elastomer. The flow rate is 0.7 ml / min, the system temperature is 35°C and the analysis time is 90 min. A set of four WATERS columns in series is used, with the trade names "STYRAGEL HMW7", "STYRAGEL HMW6E" and two "STYRAGEL HT6E".

[0050] The injected volume of the elastomer sample solution is 100 µL. The detector is a differential refractometer “WATERS 2410” with a wavelength of 810 nm. The chromatographic data processing software is the “WATERS EM POWER” system.

[0051] The calculated average molar masses are relative to a calibration curve produced from commercial standard polystyrenes “PSS READY CAL-KIT”. 1.2 Measurement of number-average (Mn), weight-average (Mw) molar masses and polydispersity index for plasticizing hydrocarbon resins

[0052] The macrostructure (Mw, Mn and Ip) of the plasticizing resin is also determined by size exclusion chromatography (SEC) according to the following protocol. Preparation of the plasticizing resin sample to be tested:

[0053] There is no special treatment of the plasticizing resin sample before analysis. It is simply solubilized at a concentration of approximately 1 g / l in tetrahydrofuran. The solution is then filtered through a 0.45 µm porosity filter before injection. SEC Analysis:

[0054] The equipment used is a WATERS ALLIANCE 2695 chromatograph. The elution solvent is tetrahydrofuran without antioxidant. The flow rate is 1 ml / min, the system temperature is 35°C and the analysis time is 45 min.

[0055] A set of four Agilent columns in series is used, with the trade names “PL GEL MIXED D”, “PL GEL MIXED E”. This set consists of two PL GEL Mixed D columns in series followed by two PL GEL Mixed E columns in series.

[0056] The injected volume of the plasticizing resin sample solution is 100 µL. The detector is a “WATERS 2410” differential refractometer with a wavelength of 810 nm. The chromatographic data processing software is the “WATERS EM POWER” system.

[0057] The calculated average molar masses are relative to a calibration curve produced from commercial standard polystyrenes from the company PSS polymer with the trade name “PSS READY CAL-KIT PSS-pskitr11” and a 162 g / mol polystyrene standard from the company PSS polymer with the trade name “PSS-ps162”. 1.3 Measurement of the glass transition temperature

[0058] The glass transition temperature Tg is measured using a differential scanning calorimeter. The analysis is carried out according to the requirements of ASTM D3418-08 (2008). 1.4 Determination of the microstructure of elastomers by NMR spectroscopy 1 < H

[0059] The determinations of the rates of the different monomer units and their microstructures within the elastomer are carried out by NMR analysis. The spectra are acquired on a 500 MHz BRUKER AVANCE spectrometer equipped with a “Broad Band” BBIz-grad 5 mm probe. The quantitative 1< H NMR experiment uses a single 30° pulse sequence and a repetition delay of 5 seconds between each acquisition. The samples are solubilized in CDCl 3 chloroform. 1.5 Determination of the quantity of plasticizing hydrocarbon resin in the resin-extended elastomer

[0060] The determination of the amount of plasticizing resin in the resin-extended elastomer is also carried out by size exclusion chromatography (SEC) analysis. Preparation of the resin-extended elastomer sample to be tested:

[0061] There is no special treatment of the resin-extended elastomer sample before analysis. It is simply solubilized at a concentration of approximately 1 g / l, in tetrahydrofuran with BHT antioxidant at 250 ppm. Then, the solution is filtered through a 0.45 µm porosity filter before injection. SEC Analysis:

[0062] The apparatus used is a WATERS Alliance 2695 chromatograph. The elution solvent is tetrahydrofuran with BHT antioxidant at 250 ppm. The flow rate is 1 mL / min, the system temperature is 35°C and the analysis time is 35 min.

[0063] A set of 3 Agilent columns in series, with the trade names "PLgel MIXED-D" and "PLgel MIXED-E", is used. This set consists of 2 Agilent PL GEL Mixed D columns and one Agilent PL GEL Mixed E column in series.

[0064] The injected volume of the resin-extended elastomer sample solution is 100 µL. The detector is a differential refractometer “WATERS 2410”, with a wavelength of 810 nm, and the chromatographic data processing software is the “WATERS EMPOWER” system.

[0065] Calibrators using a non-resin-extended elastomer with the same microstructure as the resin-extended elastomer are used. These calibrators are prepared in tetrahydrofuran with 250 ppm BHT antioxidant (butylated hydroxytoluene BHT). Several calibrators are made from a non-resin-extended elastomer at precisely known g / l concentrations to obtain a standard range. Each calibrator is injected at 100 µL into the chromatographic system. Using the data reprocessing software, each calibrator peak is integrated. It is then possible to know the total peak area of ​​each calibrator. A calibration line is then constructed by plotting the calibrator peak area as a function of concentration.

[0066] The resin-extended elastomer is then injected after the calibration line has been created. Since the resin and elastomer signals are separated using SEC columns, quantification can be performed. The peak obtained for the elastomer is then integrated using the data reprocessing software; the area of ​​said peak is then plotted on the previously constructed calibration line. It is then possible to deduce the elastomer concentration in g / L in the oil-extended elastomer (C elasto ). The concentration of the resin-extended and dissolved elastomer is known (C ech ).

[0067] The quantification of the resin rate is therefore carried out indirectly by the following relationship: Resin rate = 1 - C elasto / C sample 1.6 Determination of Mooney viscosity ML (1+4) at 100°C according to ASTM D-1646 standard for elastomers

[0068] A consistometer is used as described in ASTM D-1646. The Mooney viscosity measurement is carried out according to the following principle: the elastomer is molded in a cylindrical enclosure heated to 100 °C. After one minute of preheating, the rotor rotates within the specimen at 2 rpm -1< and the torque needed to maintain this movement after 4 minutes of rotation is measured. The Mooney viscosity (ML (1+4) ) is expressed in “Mooney Units” (MU, with 1 MU = 0.83 Nm). 1.7 Determination of the tackiness of an unvulcanized rubber composition

[0069] The stickiness of rubber compositions is measured using a tack measurement, also known as an adhesion test, called the "probe-tack" test. The probe-tack test is a contact test between a surface (a probe) and an adhesive (the composition). The test is carried out at a temperature of 70°C, which corresponds to the temperature of the rubber composition and the surface; the composition is not vulcanized. The variation of the applied force as a function of displacement is recorded. The analysis is carried out according to the requirements of ASTM D2979-01 (2009).

[0070] The results are expressed in base 100. The value in base 100 for the test sample is calculated according to the operation: (maximum force value in Newtons to separate the probe from the adhesive / test sample / maximum force value in Newtons to separate the probe from the adhesive / control) × 100). In this way, a result lower than 100 indicates a decrease in the adhesive power which corroborates a better processability of the composition. 1.8 BET and CTAB specific surface area measurement of silica

[0071] The BET specific surface area of ​​silica is determined by gas adsorption using the Brunauer-Emmett-Teller method described in "The Journal of the American Chemical Society" (Vol. 60, page 309, February 1938), and more precisely according to a method adapted from the NF ISO 5794-1 standard, annex E of June 2010 [multipoint volumetric method (5 points) - gas: nitrogen - vacuum degassing: one hour at 160°C - relative pressure range p / po: 0.05 to 0.2].

[0072] The CTAB specific surface area (S CTAB ) values ​​were determined according to standard NF ISO 5794-1, annex G of June 2010. The process is based on the adsorption of CTAB (N-hexadecyl-N,N,N-trimethylammonium bromide) on the “external” surface of the silica. 2 - DETAILED DESCRIPTION OF THE INVENTION

[0073] In this description, unless expressly indicated otherwise, all percentages (%) indicated are percentages by mass.

[0074] On the other hand, any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than "a" to less than "b" (i.e., excluding the limits a and b) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from "a" up to "b" (i.e., including the strict limits a and b).

[0075] In the present application, "pce" (usually "phr" in English) means the part by weight of a constituent per hundred parts by weight of elastomers.

[0076] In the context of the invention, the carbon products mentioned in the description may be of fossil or bio-sourced origin. In the latter case, they may be, partially or totally, derived from biomass or obtained from renewable raw materials derived from biomass. This includes in particular polymers, plasticizers, fillers, etc. 2.1 - Resin-extended elastomer

[0077] The subject of the invention is a resin-extended elastomer, the elastomer of which is a synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol and the resin of which is a plasticizing hydrocarbon resin and the content of plasticizing hydrocarbon resin in a range from 30 to 100 phr, the resin-extended elastomer being obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon resin in the liquid state and the resin-extended elastomer having a Mooney viscosity index greater than or equal to 40 UM.

[0078] For the purposes of the present invention, the term “resin-extended elastomer” means a solid composite-type material formed from an elastomer and a resin intimately mixed with each other. Elastomer

[0079] A first constituent of the resin-extended elastomer in accordance with the invention is a synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol.

[0080] By "elastomer (or indistinctly "rubber"; the two terms being considered synonymous) of the diene type" is meant in a known manner an elastomer (meaning one or more elastomers) consisting at least in part (i.e., a homopolymer or a copolymer) of diene monomer units (monomers bearing two carbon-carbon double bonds, conjugated or not).

[0081] Diene elastomers can be classified into two categories: "essentially unsaturated" or "essentially saturated". "Essentially unsaturated" generally means a diene elastomer derived at least in part from conjugated diene monomers, having a content of units or motifs of diene origin (conjugated dienes) which is greater than 15% (mol %); thus, diene elastomers such as butyl rubbers or copolymers of dienes and alpha-olefins such as EPDM do not fall within the preceding definition and may be described in particular as "essentially saturated" diene elastomers (low or very low content of motifs of diene origin, always less than 15% (mol %)).In the category of “essentially unsaturated” diene elastomers, a “highly unsaturated” diene elastomer is understood to mean in particular a diene elastomer having a content of units of diene origin (conjugated dienes) which is greater than 50% (mol %).

[0082] For the purposes of the present invention, the term "synthetic elastomer" means an elastomer obtained by chemical synthesis from bio-sourced monomers or from petroleum chemistry. A synthetic elastomer is therefore distinguished from natural rubber, which is a natural diene elastomer.

[0083] Given these definitions, the term synthetic diene elastomer capable of being used in the resin-extended elastomer in accordance with the invention is understood more particularly to mean: (a) any homopolymer of a conjugated diene monomer, in particular any homopolymer obtained by polymerization of a conjugated diene monomer having from 4 to 12 carbon atoms; (b) any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or more aromatic vinyl compounds having from 8 to 20 carbon atoms; (c) a ternary copolymer obtained by copolymerization of ethylene, an α-olefin having 3 to 6 carbon atoms with a non-conjugated diene monomer having from 6 to 12 carbon atoms, such as for example elastomers obtained from ethylene, propylene with a non-conjugated diene monomer of the aforementioned type such as in particular hexadiene-1,4, ethylidene norbornene, dicyclopentadiene;(d) a copolymer of isobutene and isoprene (butyl rubber), as well as halogenated, in particular chlorinated or brominated, versions of this type of copolymer, (e) any copolymer obtained by copolymerization of one or more conjugated dienes with ethylene, an acyclic aliphatic α-monoolefin having 3 to 18 carbon atoms or a mixture thereof such as, for example, those described in WO 2005 / 028526, WO 2004 / 035639 and WO 2007 / 054224. ;

[0084] Although applicable to any type of synthetic diene elastomer, those skilled in the art will understand that the present invention is preferably implemented with essentially unsaturated diene elastomers, in particular of type (a) or (b) above.

[0085] Preferably, the synthetic diene elastomer comprises at least one conjugated diene monomer having from 4 to 12 carbon atoms.

[0086] It can therefore be a homopolymer of conjugated diene monomers having from 4 to 12 carbon atoms or a copolymer resulting from the polymerization of conjugated diene monomers having from 4 to 12 carbon atoms with another polymerizable monomer.

[0087] Preferably, the conjugated diene monomer having 4 to 12 carbon atoms of the synthetic diene elastomer is chosen from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadienes such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene and mixtures of these monomers.

[0088] More preferably, the conjugated diene monomer having 4 to 12 carbon atoms is chosen from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene and mixtures of these monomers.

[0089] The other polymerizable monomer with conjugated diene monomers having 4 to 12 carbon atoms (first monomer) can be: a conjugated diene monomer having from 4 to 12 carbon atoms different from the first monomer; a vinyl aromatic monomer having from 8 to 20 carbon atoms; an alpha-olefin monomer such as propylene, 1-butene, isobutylene, pentene, methylpentene, 1-hexene; ethylene; and a mixture of these monomers.

[0090] Preferably, the other polymerizable monomer is a vinylaromatic monomer having from 8 to 20 carbon atoms. Thus, the synthetic diene elastomer usable in the resin-extended elastomer in accordance with the invention further comprises at least one vinylaromatic monomer having from 8 to 20 carbon atoms. In this case, it is a copolymer.

[0091] Suitable vinylaromatic monomers having from 8 to 20 carbon atoms include styrenic monomers, namely any monomer comprising styrene, unsubstituted or substituted.Among the substituted styrenes that may be mentioned are, for example, methylstyrenes (for example, o-methylstyrene, m-methylstyrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethylstyrene, alpha-4-dimethylstyrene or diphenylethylene), para-tert-butylstyrene, chlorostyrenes (for example, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or 2,4,6-trichlorostyrene), bromostyrenes (for example, o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or 2,4,6-tribromostyrene), fluorostyrenes (e.g. o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene or 2,4,6-trifluorostyrene) or para-hydroxy-styrene.

[0092] More preferably, the vinylaromatic monomer having from 8 to 20 atoms is chosen from the group consisting of styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, the commercial mixture “vinyl-toluene”, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene and mixtures of these monomers.

[0093] More preferably still, the vinylaromatic monomer having 8 to 20 carbon atoms is styrene.

[0094] In summary, the synthetic diene elastomer that can be used in the context of the invention is preferably chosen from the group consisting of polybutadienes (abbreviated as "BR"), synthetic polyisoprenes (abbreviated as "IR"), butadiene copolymers, isoprene copolymers and mixtures of these elastomers. Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers (abbreviated as "SBR"), isoprene-butadiene copolymers (abbreviated as "BIR"), isoprene-styrene copolymers (abbreviated as "SIR"), and isoprene-butadiene-styrene copolymers (abbreviated as "SBIR").

[0095] Preferably, the synthetic diene elastomer usable in the resin-extended elastomer in accordance with the invention is a butadiene-styrene copolymer.

[0096] In the case of copolymers of type (b), these may contain from 20 to 99% by weight of diene units and from 1 to 80% by weight of vinylaromatic units.

[0097] Preferably, when the synthetic diene elastomer usable in the context of the present invention comprises vinylaromatic monomers having from 8 to 20 carbon atoms (in particular this monomer is styrene), the level of this monomer is within a range from 3 to 20% by weight relative to the total weight of the elastomer, more preferably ranging from 5 to 16% by weight relative to the total weight of the elastomer.

[0098] Preferably, when the synthetic diene elastomer usable in the context of the present invention comprises vinylaromatic monomers having from 8 to 20 carbon atoms (in particular this monomer is styrene) and 1,3-butadiene monomers, the content of 1,2-vinyl butadiene units is within a range from 4 to 30% by weight relative to the total weight of the polybutadiene part, more preferably ranging from 5 to 25% by weight relative to the total weight of the polybutadiene part.

[0099] The synthetic diene elastomers usable in the context of the present invention may have any microstructure which depends on the polymerization conditions used, in particular the presence or absence of a modifying and / or randomizing agent and the quantities of modifying and / or randomizing agent used.

[0100] The synthetic diene elastomers that can be used in the context of the present invention can, for example, be block, random, sequenced, microsequenced, and are solution synthesized; they can be coupled and / or star-shaped or even functionalized with a coupling and / or star-shaping or functionalizing agent. Preferably, in the case of a copolymer based on conjugated diene monomers having from 4 to 12 carbon atoms (in particular 1,3-butadiene) and vinylaromatic monomers having from 8 to 20 carbon atoms (in particular styrene), these two monomers are distributed statistically along the polymer chain.

[0101] In one embodiment of the invention, the synthetic diene elastomers usable in the context of the present invention may be synthetic diene elastomers functionalized by a function chosen from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane, carboxylic groups, polyether groups, epoxide groups and mixtures thereof.

[0102] For coupling to carbon black, examples that may be mentioned are functional groups comprising a C-Sn bond or amine functional groups such as aminobenzophenone for example. For coupling to a reinforcing inorganic filler such as silica, examples that may be mentioned are silanol or polysiloxane functional groups having a silanol end (as described for example in FR2740778 or US6013718, and WO2008 / 141702), alkoxysilane groups (as described for example in FR2765882 or US5977238), carboxylic groups (as described for example in WO01 / 92402 or US6815473, WO2004 / 096865 or US2006 / 0089445) or polyether groups (as described for example in EP1 127909 or US6503973, WO2009 / 000750 and WO2009 / 000752). Functional elastomers may also be mentioned as those prepared by the use of a functional initiator, in particular those carrying an amine or tin function (see for example WO2010 / 072761).Other examples of functionalized elastomers include elastomers (such as synthetic SBR, BR, or IR) of the epoxidized type.

[0103] Preferably, this function is chosen from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane.

[0104] Even more preferably, this function is chosen from the group consisting of functional groups comprising a silanol and functional groups comprising an alkoxysilane.

[0105] The functional group carrying the function can be located at the end of the chain, that is to say at one end of the main linear elastomer chain. We will then say that the diene elastomer is functionalized "at the end of the chain" or "at the end of the chain". It is generally an elastomer obtained by reaction of a living elastomer on a functionalizing agent, that is to say any molecule at least monofunctional, the function being any type of chemical group known by those skilled in the art to react with a living chain end.

[0106] This chemical group can be located in the main linear elastomer chain. We will then say that the diene elastomer is coupled or functionalized "in the middle of the chain", as opposed to the "end of the chain" position and although the group is not located precisely in the middle of the elastomer chain. It is generally an elastomer obtained by reaction of two chains of the living elastomer on a coupling agent, that is to say any molecule at least difunctional, the function being any type of chemical group known by those skilled in the art to react with a living chain end.

[0107] This group can be central to which n elastomer chains (n>2) are linked forming a star structure of the elastomer. We will then say that the diene elastomer is star-shaped. It is generally an elastomer obtained by reaction of n chains of the living elastomer on a star-forming agent, that is to say any multifunctional molecule, the function being any type of chemical group known by those skilled in the art to react with a living chain end.

[0108] Those skilled in the art will understand that a functionalization reaction with an agent comprising more than one reactive function with respect to the living elastomer results in a mixture of functionalized species at the end of the chain and in the middle of the chain, constituting the linear chains of the functionalized diene elastomer, as well as, where appropriate, star-shaped species. Depending on the operating conditions, mainly the molar ratio of the functionalizing agent to the living chains, certain species are in the majority in the mixture.

[0109] Preferably, the synthetic diene elastomers usable in the context of the present invention carry a mid-chain or chain-end functional group, more preferably a chain-end functional group.

[0110] The synthetic diene elastomers usable in the context of the present invention have a high number-average molar mass Mn, i.e. an Mn in a range from 250,000 g / mol to 450,000 g / mol. Those skilled in the art know how to adapt the synthesis conditions of synthetic diene elastomers to obtain such Mn. The Mn is measured according to the method described in paragraph 1.1.

[0111] Preferably, the synthetic diene elastomers that can be used in the context of the present invention are low Tg elastomers. By low Tg is meant a Tg less than or equal to -60°C. Those skilled in the art know how to adapt the microstructure of synthetic diene elastomers to obtain such Tg. It is understood that the Tg of the synthetic diene elastomer used in the formulation of the resin-extended elastomer is measured on the synthetic diene elastomer prior to its mixing with the plasticizing hydrocarbon resin. The Tg is measured according to the method described in paragraph 1.3.

[0112] Preferably, the synthetic diene elastomers usable in the context of the present invention have a Tg comprised in a range from -110°C to -60°C, more preferably from -95°C to -65°C.

[0113] The synthetic diene elastomers usable in the context of the present invention are obtained by solution polymerization, preferably by homogeneous solution polymerization. Any type of solution polymerization well known to those skilled in the art may be used, such as, for example, anionic polymerization or coordination polymerization.

[0114] Solution polymerization is well known to those skilled in the art and differs from emulsion (or dispersed medium) polymerization in that the monomers used and the elastomer being synthesized are soluble in the polymerization solvent. At the end of the polymerization reaction, the elastomer formed is also soluble in the polymerization solvent and is recovered by evaporation of said solvent or by filtration. In this type of polymerization, the polymerization solvent is very often a hydrocarbon solvent. On the contrary, in emulsion polymerization, the polymerization solvent is water or an aqueous solution and the polymerizable monomer is insoluble in this polymerization solvent. Micelles are then formed in which the polymerization reaction takes place.At the end of an emulsion polymerization (or in a dispersed medium) an elastomer is obtained in the form of latex, that is to say a stable emulsion of elastomer particles in an aqueous solution. The synthetic diene elastomers usable in the context of the present invention synthesized in solution are therefore not in the form of latex. Plasticizing hydrocarbon resin

[0115] The second constituent of the resin-extended elastomer according to the invention is a plasticizing hydrocarbon resin.

[0116] As known to those skilled in the art, the term “resin” is reserved in the present application, by definition, for a compound which is solid at room temperature (23°C), as opposed to a plasticizer which is liquid at room temperature such as an oil.

[0117] Plasticizing resins are polymers well known to those skilled in the art. They are hydrocarbon resins essentially based on carbon and hydrogen but which may contain other types of atoms, usable in particular as plasticizing agents or tackifying agents in polymer matrices. They are by nature miscible (i.e., compatible) at the rates used with the diene elastomer compositions for which they are intended, so as to act as true diluting agents. They have been described for example in the work entitled "Hydrocarbon Resins" by R. Mildenberg, M. Zander and G. Collin (New York, VCH, 1997, ISBN 3-527-28617-9) of which chapter 5 is devoted to their applications, in particular in pneumatic rubber (5.5. "Rubber Tires and Mechanical Goods").They can be aliphatic, cycloaliphatic, aromatic, hydrogenated aromatic, of the aliphatic / aromatic type, i.e. based on aliphatic and / or aromatic monomers. They can be natural or synthetic, based on petroleum or not (if this is the case, also known as petroleum resins). They are preferably exclusively hydrocarbon-based, i.e. they only contain carbon and hydrogen atoms. Their Tg is preferably greater than or equal to 0°C, preferably greater than or equal to 20°C (most often within a range from 30°C to 95°C). In the present application, the expressions “plasticizing resins”, “hydrocarbon resins” and “plasticizing hydrocarbon resins” are interchangeable.

[0118] As is known, these plasticizing hydrocarbon resins can also be referred to as thermoplastic resins in that they soften upon heating and can therefore be molded. They can also be defined by a softening point or temperature. The softening temperature of a plasticizing hydrocarbon resin is generally approximately 50°C to 60°C higher than its Tg value. The softening point is measured according to ISO 4625 of 2012 (Ring and Ball method).

[0119] Preferably, the plasticizing hydrocarbon resin usable in the context of the present invention has a Tg greater than or equal to 0°C, preferably greater than or equal to 20°C, preferably greater than or equal to 30°C (in particular between 30°C and 95°C). It is understood that the Tg of the plasticizing hydrocarbon resin used in the formulation of the resin-extended elastomer in accordance with the invention is measured on the plasticizing hydrocarbon resin prior to its mixing with the synthetic diene elastomer. The Tg of the plasticizing hydrocarbon resin is measured according to the method described in paragraph 1.3.

[0120] Preferably, the plasticizing hydrocarbon resin usable in the context of the present invention has a softening point greater than or equal to 50°C (in particular between 50°C and 150°C) measured according to standard ISO 4625 of 2012 (“Ring and Ball” method).

[0121] Preferably, the plasticizing hydrocarbon resin usable in the context of the present invention has a number-average molar mass (Mn) of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol. The Mn of the plasticizing hydrocarbon resin is measured according to the method described in paragraph 1.2.

[0122] Preferably, the plasticizing hydrocarbon resin usable in the context of the present invention has a polymolecularity index (Ip) of less than 3 (reminder: Ip = Mw / Mn with Mw average molar mass by weight).

[0123] More preferably, the plasticizing hydrocarbon resin usable in the context of the present invention may have a Tg greater than or equal to 20°C, preferably greater than or equal to 30°C and an Mn of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol.

[0124] More preferably, the plasticizing hydrocarbon resins usable in the context of the present invention may have all of the preferential characteristics above.

[0125] Preferably, the plasticizing hydrocarbon resin usable in the context of the present invention is chosen from the group consisting of aliphatic resins, aromatic resins and mixtures of these resins.

[0126] Examples of such plasticizing hydrocarbon resins that can be used in the context of the present invention include those chosen from the group consisting of cyclopentadiene homopolymer or copolymer resins (abbreviated CPD), dicyclopentadiene homopolymer or copolymer resins (abbreviated DCPD), terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, mixtures of C5-cut homopolymer or copolymer resins and C9-cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins and mixtures of these resins.

[0127] Among the above copolymer plasticizing hydrocarbon resins, mention may be made more particularly of those chosen from the group consisting of CPD / vinylaromatic copolymer resins, DCPD / vinylaromatic copolymer resins, CPD / terpene copolymer resins, DCPD / terpene copolymer resins, terpene phenol copolymer resins, CPD / C5 cut copolymer resins, DCPD / C5 cut copolymer resins, CPD / C9 cut copolymer resins, DCPD / C9 cut copolymer resins, blends of C5 cut and C9 cut resins, terpene / vinylaromatic copolymer resins, terpene / phenol copolymer resins, C5 cut / vinylaromatic copolymer resins, and blends of these resins.

[0128] The term "terpene" here includes the monomers alphapinene, beta-pinene and limonene in a known manner; preferentially a limonene monomer is used, a compound which is present in a known manner in the form of three possible isomers: L-limonene (levorotatory enantiomer), D-limonene (dextrorotatory enantiomer), or dipentene, racemic of the dextrorotatory and levorotatory enantiomers.

[0129] Suitable vinylaromatic monomers include, for example, styrene, alpha-methylstyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyltoluene, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, hydroxystyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, and any vinylaromatic monomer derived from a C9 fraction (or more generally from a C8 to C10 fraction).

[0130] More preferably still, the plasticizing hydrocarbon resins which can be used in the context of the present invention are a C5 cut / C9 cut copolymer resin or a mixture of these resins.

[0131] All of the above plasticizing hydrocarbon resins are well known to those skilled in the art and commercially available, for example sold by the company DRT under the name "Dercolyte" for polylimonene resins, by the company Neville Chemical Company under the name "Super Nevtac", by Kolon under the name "Hikorez" or by the company Exxon Mobil under the name "Escorez" for C5 / styrene cut resins or C5 / C9 cut resins, or by the company Struktol under the name "40 MS" or "40 NS" (mixtures of aromatic and / or aliphatic resins). Resin-extended elastomer

[0132] The intimate blending of a synthetic diene elastomer as described above (including its preferred embodiments) and a plasticizing hydrocarbon resin as described above (including its preferred embodiments) makes it possible to obtain a new material: a resin-extended elastomer. Since the two constituents of this material are intimately blended with each other, a single (unique) Tg value is obtained when this parameter is measured for the resin-extended elastomer. This Tg of the resin-extended elastomer is different from that of the synthetic diene elastomer and that of the plasticizing hydrocarbon resin measured before their blending. Surprisingly, this resin-extended elastomer has a good Mooney viscosity, presuming good processability.The resin-extended elastomer according to the invention has the advantage of being able to be used for the manufacture of rubber compositions, in particular intended for the manufacture of tires. Its use in this type of composition allows better processability of the composition in the various mixing tools. It limits the stickiness of the rubber compositions containing it compared to a rubber composition comprising an elastomer of the same microstructure but not extended with resin and the same content of hydrocarbon resin. Thus, the rubber composition comprising the resin-extended elastomer according to the invention has better processability and does not damage or only very little damage the mixing tools.

[0133] The resin-extended elastomer in accordance with the present invention has a Mooney viscosity (measured according to the method described in paragraph 1.6) greater than or equal to 40 UM (with UM = Mooney unit and 1 UM = 0.83 Nm), more preferably within a range from 50 to 75 UM.

[0134] The level of plasticizing hydrocarbon resin in the resin-extended elastomer is in the range of 30 to 100 pce, preferably 30 to 80 pce.

[0135] The resin-extended elastomer according to the invention is obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon resin in the liquid state.

[0136] For the purposes of the present invention, the term "synthetic diene elastomer in solution" means a homogeneous solution of a synthetic diene elastomer, i.e. the organic solvent and said elastomer form only one phase visible to the naked eye. There is no precipitate or suspension of particles of said elastomer in the solution.

[0137] The organic solvent may be any solvent compatible with the monomers of the synthetic diene elastomer, with the synthetic diene elastomer and with the plasticizing hydrocarbon resin. Preferably, the organic solvent is aliphatic or alicyclic. Examples that may be mentioned include n-pentane, isopentane, isoamylenes (2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene), 2,2-dimethylbutane, 2,2-dimethylpropane (neopentane), n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, n-hexane, methylcyclopentane and methylcyclohexane, as well as mixtures of these compounds. Mention may also be made, as organic solvent, of aromatic hydrocarbons such as, for example, benzene or toluene.

[0138] For the purposes of the present invention, the term "plasticizing hydrocarbon resin in the liquid state" means a plasticizing hydrocarbon resin which is in the solid state at room temperature and which has undergone a process to change to the liquid state. For example, the plasticizing hydrocarbon resin may be heated, using any technique well known to those skilled in the art, to a temperature above its softening temperature. Another example for obtaining a plasticizing hydrocarbon resin in the liquid state consists of solubilizing said hydrocarbon resin in an organic solvent in which it is compatible. This technique is also well known to those skilled in the art. This organic solvent may be identical to or different from that in which the synthetic diene elastomer is found in solution.When the organic solvent used to solubilize the plasticizing hydrocarbon resin is different from the organic solvent in which the synthetic diene elastomer is found, then the solvent for solubilizing the resin must be compatible with that in which the elastomer is found. By compatible, we mean that the mixture of these two solvents forms only one phase visible to the naked eye. 2.2 Process for obtaining the resin-extended elastomer

[0139] The invention also relates to a process for obtaining said resin-extended elastomer, the process comprising at least: (a) a step of bringing at least one synthetic diene elastomer in solution in an organic solvent into contact with at least one plasticizing hydrocarbon resin, said synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol, (b) a mixing step to obtain a homogeneous solution of synthetic diene elastomer and plasticizing hydrocarbon resin, (c) a steam stripping step to recover a gaseous fraction enriched in organic solvent and an aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin; and (d) a step of recovering the resin-extended elastomer from the aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin.

[0140] This process of obtaining a resin-extended elastomer can be a discontinuous or continuous process.

[0141] The first step of the process concerns bringing at least one synthetic diene elastomer in solution in an organic solvent into contact with at least one plasticizing hydrocarbon resin, said synthetic diene elastomer having a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol. This contacting can be carried out in any reactor well known to those skilled in the art.

[0142] The solvent in which the synthetic diene elastomer is present may be any inert hydrocarbon solvent, preferably aliphatic or alicyclic. Examples include n-pentane, isopentane, isoamylenes (2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene), 2,2-dimethylbutane, 2,2-dimethylpropane (neopentane), n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, n-hexane, methylcyclopentane and methylcyclohexane, as well as mixtures of these compounds. Examples of organic solvents include aromatic hydrocarbons such as benzene or toluene.

[0143] In the process according to the invention, the synthetic diene elastomer in solution in the organic solvent can be obtained either by dissolving said elastomer in said organic solvent or by polymerization, in solution in said organic solvent, of the corresponding monomers of said elastomer.

[0144] The dissolution of the synthetic diene elastomer is carried out by any method well known to those skilled in the art, for example by immersing the balls of said elastomer in a reactor filled with the organic solvent and stirring the reaction medium, possibly also heating it, in order to obtain a synthetic diene elastomer in solution in the solvent.

[0145] In a variant of the process according to the invention, the synthetic diene elastomer in solution is obtained by polymerization in solution in said organic solvent of the corresponding monomers of said elastomer. In other words, prior to step (a), the process of the invention may comprise a step (a') in which a synthetic diene elastomer is polymerized in solution, preferably in homogeneous solution (i.e. in the aforementioned organic solvent), from the corresponding monomers. In this step (a'), preferably, at least one conjugated diene monomer having from 4 to 12 carbon atoms is polymerized.This conjugated diene monomer having 4 to 12 carbon atoms can be selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C1-C5 alkyl)-1,3-butadienes such as for example 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene and mixtures of these monomers. More preferably, the conjugated diene monomer having 4 to 12 carbon atoms is chosen from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene and mixtures of these monomers. According to implementations of the process of the invention, the conjugated diene monomer having 4 to 12 carbon atoms (first monomer) can also be copolymerized with at least one other polymerizable monomer, in particular which can be: . a conjugated diene monomer having from 4 to 12 carbon atoms different from the first monomer; a vinyl aromatic monomer having from 8 to 20 carbon atoms; an alpha-olefin monomer such as propylene, 1-butene, isobutylene, pentene, methylpentene, 1-hexene; ethylene.

[0146] Preferably, the other polymerizable monomer is a vinylaromatic monomer having from 8 to 20 carbon atoms. Suitable vinylaromatic compounds include in particular styrenic monomers, namely any monomer comprising styrene, unsubstituted or substituted.Among the substituted styrenes that may be mentioned are, for example, methylstyrenes (for example, o-methylstyrene, m-methylstyrene or p-methylstyrene, alpha-methylstyrene, alpha-2-dimethylstyrene, alpha-4-dimethylstyrene or diphenylethylene), para-tert-butylstyrene, chlorostyrenes (for example, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene or 2,4,6-trichlorostyrene), bromostyrenes (for example, o-bromostyrene, m-bromostyrene, p-bromostyrene, 2,4-dibromostyrene, 2,6-dibromostyrene or 2,4,6-tribromostyrene), fluorostyrenes (e.g. o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, 2,4-difluorostyrene, 2,6-difluorostyrene or 2,4,6-trifluorostyrene) or para-hydroxy-styrene.Preferably, the vinylaromatic monomer having from 8 to 20 carbon atoms of the synthetic elastomer usable in the process according to the invention is chosen from the group consisting of styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene and households of these monomers. Even more preferably, the vinylaromatic monomer having from 8 to 20 carbon atoms is styrene.Thus, in one embodiment of the process of the invention, step (a') of the process is a step in which a diene elastomer is polymerized in solution, preferably in homogeneous solution, from at least one conjugated diene monomer having from 4 to 12 carbon atoms (preferably this monomer is 1,3-butadiene or 2-methyl-1,3-butadiene) and at least one vinylaromatic monomer having from 8 to 20 carbon atoms (preferably styrene).

[0147] The polymerization can be an anionic polymerization or a catalytic chain polymerization (depending on the coordination-insertion mechanism). These types of polymerizations are well known to those skilled in the art and have been extensively described in the literature.

[0148] Briefly, in the context of anionic polymerization, it is initiated for example by means of a polymerization initiator which can be any known anionic, mono- or polyfunctional initiator. However, an initiator containing an alkali metal such as lithium or an alkaline earth metal such as barium is preferably used. Suitable organolithium initiators include those containing one or more carbon-lithium bonds such as n-butyllithium (n-BuLi), or lithium amides.

[0149] Briefly, in the context of a chain polymerization by coordination catalysis, a catalytic system based on rare earth metal or titanium is used. Such systems have been described in particular in documents WO02 / 38636, WO03 / 097708 and WO2007 / 045417.

[0150] In one implementation of the method of the invention, it may further comprise a step (a") in which the synthetic diene elastomer obtained in step (a') is modified. This step consists of introducing a chemical function into the chain of the polymer during synthesis or at the end of the chain. Such methods have been described in particular in applications WO2009133068 and WO2011042507.

[0151] Preferably, in the process according to the invention, the synthetic diene elastomer can be functionalized by a function chosen from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane, carboxylic groups, polyether groups, epoxide groups and mixtures of the latter.

[0152] More preferably, in the process according to the invention, the synthetic diene elastomer can be functionalized by a function chosen from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane and mixtures of the latter.

[0153] In the process according to the invention, the synthetic diene elastomer dissolved in the organic solvent or obtained at the end of step (a') and / or (a") has a number-average molar mass in a range from 250,000 g / mol to 450,000 g / mol. The Mn is measured according to the method described in paragraph 1.1.

[0154] Preferably, in the process according to the invention, the synthetic diene elastomer dissolved in the organic solvent or obtained at the end of step (a') and / or (a") has a glass transition temperature of less than or equal to -60°C. Preferably, said synthetic diene elastomer has a transition temperature in a range from -110°C to -60°C, preferably from -95°C to -65°C. The Tg is measured according to the method described in paragraph 1.3.

[0155] The resin used in the process of the invention during step (a) is a plasticizing hydrocarbon resin. As indicated previously, this plasticizing hydrocarbon resin is in the solid state at room temperature (23°C). These plasticizing hydrocarbon resins can also be described as thermoplastic resins in the sense that they soften upon heating and can thus be molded. They can also be defined by a softening point or temperature. The softening temperature of a plasticizing resin is generally approximately 50 to 60°C higher than its Tg value. The softening point is measured according to ISO 4625 of 2012 (“Ring and Ball” method).

[0156] Preferably, the plasticizing hydrocarbon resin usable in the process of the invention has a Tg greater than or equal to 0°C, preferably greater than or equal to 20°C, preferably greater than or equal to 30°C (in particular between 30°C and 95°C). The Tg is measured according to the method described in paragraph 1.3.

[0157] Preferably, the plasticizing hydrocarbon resin usable in the process of the invention has a softening point greater than or equal to 50°C (in particular between 50°C and 150°C) measured according to the ISO 4625 standard of 2012 (“Ring and Ball” method).

[0158] Preferably, the plasticizing hydrocarbon resin usable in the process of the invention has a number-average molar mass (Mn) of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol. The Mn is measured according to the method described in paragraph 1.2

[0159] Preferably, the plasticizing hydrocarbon resin usable in the process of the invention has a polymolecularity index (Ip) of less than 3 (reminder: Ip = Mw / Mn with Mw average molar mass by weight). More preferably, the plasticizing hydrocarbon resin in the process of the invention may have a Tg greater than or equal to 20°C, preferably greater than or equal to 30°C and an Mn of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol.

[0160] More preferably, the plasticizing hydrocarbon resin usable in the process of the invention may have all of the preferential characteristics above.

[0161] Preferably, the plasticizing hydrocarbon resin usable in the process of the invention is chosen from the group consisting of aliphatic resins, aromatic resins and mixtures of these resins.

[0162] Examples of such plasticizing hydrocarbon resins that can be used in the context of the present invention include those chosen from the group consisting of cyclopentadiene homopolymer or copolymer resins (abbreviated CPD), dicyclopentadiene homopolymer or copolymer resins (abbreviated DCPD), terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, mixtures of C5-cut homopolymer or copolymer resins and C9-cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins and mixtures of these resins.

[0163] Preferably, during contact in step (a), the plasticizing hydrocarbon resin is in the liquid state. In other words, the plasticizing hydrocarbon resin in the liquid state can therefore preferably be injected, by any appropriate means known to those skilled in the art, into the solvent solution containing the synthetic diene elastomer.

[0164] According to one embodiment of the method of the invention, the plasticizing hydrocarbon resin in the liquid state can be obtained by heating said resin to a temperature greater than or equal to its softening temperature. This heating step is carried out by any means well known to those skilled in the art, for example using a reactor comprising heating and stirring means. Those skilled in the art know how to determine the temperature at which the heating is carried out and the heating time, depending on the plasticizing hydrocarbon resin used, in order to obtain a plasticizing hydrocarbon resin in the liquid state and whose viscosity allows it to be pumped for use in step (a). The temperature at which the heating is carried out is greater than or equal to the softening temperature of said resin.For example, the plasticizing hydrocarbon resin can be heated to a temperature ranging from 50°C to 200°C for a time ranging from 10 min to 2 hours.

[0165] According to another embodiment of the process of the invention, the plasticizing hydrocarbon resin in the liquid state can be obtained by dissolving said resin in an organic solvent identical to or different from the organic solvent in which the synthetic diene elastomer is found. A person skilled in the art knows how to choose the appropriate solvent depending on the plasticizing hydrocarbon resin used. Preferably, this organic solvent can be any inert hydrocarbon solvent, preferably aliphatic or alicyclic. Examples include n-pentane, isopentane, isoamylenes (2-methyl-2-butene, 2-methyl-1-butene and 3-methyl-1-butene), 2,2-dimethylbutane, 2,2-dimethylpropane (neopentane), n-heptane, n-octane, isooctane, cyclopentane, cyclohexane, n-hexane, methylcyclopentane and methylcyclohexane, as well as mixtures of these compounds.Aromatic hydrocarbons such as benzene or toluene may also be mentioned as organic solvents. Preferably, the organic solvent in which the plasticizing hydrocarbon resin is dissolved is identical to that in which the synthetic diene elastomer is found. The dissolution of the plasticizing hydrocarbon resin can be carried out at room temperature or by heating the plasticizing hydrocarbon resin / organic solvent mixture. It is understood that when heating this mixture, the heating temperature must not be higher than the boiling point of the organic solvent to prevent the latter from evaporating.

[0166] The mixing step of the process according to the invention (step (b)) is carried out by any means well known to those skilled in the art, for example by stirring and optionally by heating the reaction medium. This step makes it possible to obtain a homogeneous solution of synthetic diene elastomer and plasticizing hydrocarbon resin. Stirring can be carried out, for example, with stirring devices in the reactor. By "homogeneous solution of synthetic diene elastomer and plasticizing hydrocarbon resin" within the meaning of the present invention, the solution of synthetic diene elastomer and the plasticizing hydrocarbon resin in the liquid state after mixing form only a single liquid phase to the naked eye. There is no precipitate or suspended particles in the reaction medium.

[0167] The process according to the invention then comprises a steam stripping step. The steam stripping step is well known to those skilled in the art and makes it possible to recover a gaseous fraction enriched in organic solvent and an aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin. It is carried out in a stripping column. Those skilled in the art know how to adapt, depending on the quantity of organic solvent and possibly the quantity of unconverted monomers present at the inlet of the stripping column, the quantity of steam to be supplied to recover the elastomer in the form of an aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin.

[0168] Upon contact with the water vapor and the water present in the stripping column, the synthetic diene elastomer and the plasticizing hydrocarbon resin, both being hydrophobic, spontaneously coagulate in the form of particles of synthetic diene elastomer and plasticizing hydrocarbon resin. This coagulation allows the hydrocarbon resin to be trapped in the synthetic diene elastomer and to form the resin-extended elastomer. Since the organic solvent is volatile, it is carried along with the water vapor and a gaseous fraction enriched in organic solvent is obtained.

[0169] Preferably, this gaseous fraction enriched in organic solvent can, after treatment, be recycled to step (a). The recycled organic solvent can thus be used as a polymerization solvent or for the solubilization of the plasticizing hydrocarbon resin or the synthetic diene elastomer.

[0170] The step of recovering the resin-extended elastomer from the aqueous dispersion of synthetic diene elastomer particles and plasticizing hydrocarbon resin is well known to those skilled in the art and can be carried out by any conventional means of separating a solid and a fluid, such as decantation, centrifugation (spinning), filtration, drying. Preferably, the recovery of the resin-extended elastomer is carried out by drying the aqueous dispersion of synthetic diene elastomer particles and plasticizing hydrocarbon resin, for example by placing said dispersion in a thermostatically controlled oven or by sending this suspension into a cylinder tool. The purpose of step (d) is to remove the aqueous solution in order to recover the resin-extended elastomer according to the invention in the form of a dry solid.

[0171] Preferably, prior to recovery step (d), the process according to the invention may comprise at least one washing step (c') of the aqueous dispersion of particles of synthetic diene elastomer and plasticizing hydrocarbon resin. This optional step makes it possible to eliminate residual impurities which would not have been eliminated, for example, during the steam stripping step.

[0172] The resin-extended elastomer can then be recovered and packaged in a manner known per se, for example in the form of balls.

[0173] Surprisingly, the resin-extended elastomer as defined above (including its preferred embodiments) or obtainable according to the method defined above (including its preferred embodiments), in accordance with the invention, has a satisfactory Mooney viscosity despite the high number-average molar mass of the elastomer used as a constituent and the presence of plasticizing resin. This satisfactory Mooney viscosity is a good indicator of the low tackiness of this material. This resin-extended elastomer in accordance with the invention can be advantageously used, for a tire application, in a reinforced rubber composition, the processability of which on mixing tools it improves. This rubber composition is also the subject of the present invention. 2.3 Rubber composition

[0174] Thus, as explained above, another subject of the present invention relates to a rubber composition based on at least one resin-extended elastomer as defined above or capable of being obtained by the process as described above and at least one reinforcing filler. It should be understood that the rubber composition may comprise one or more of these resin-extended elastomers in accordance with the invention.

[0175] By "composition based on", we mean, within the meaning of this document, a composition comprising the mixture and / or the reaction product of the different constituents used, some of these basic constituents being capable of, or intended to react with each other, at least in part, during the different phases of manufacture of the composition, in particular during its extrusion or during the mixing phase.

[0176] The rubber compositions in accordance with the invention may be in the crosslinked state or in the non-crosslinked state, in other words crosslinkable.

[0177] The resin-extended elastomer according to the invention, including its preferred embodiments, may be used, according to various variants, alone in the compositions or in a blend with at least one other conventional diene elastomer. Preferably, this other conventional diene elastomer is chosen from the group consisting of polybutadienes, synthetic polyisoprenes, natural rubber, butadiene copolymers, isoprene copolymers and blends of these elastomers. Such copolymers are more preferably chosen from the group consisting of butadiene-styrene copolymers, isoprene-butadiene copolymers, isoprene-styrene copolymers and isoprene-butadiene-styrene copolymers. It is also possible to consider blending (mixing) with any synthetic elastomer other than diene, or even with any other polymer other than elastomer, for example a thermoplastic polymer.

[0178] The rubber compositions in accordance with the invention comprise, as resin-extended elastomer, a resin-extended elastomer the following characteristics of which are met; the number-average molar mass of the synthetic diene elastomer is in a range from 250,000 g / mol to 450,000 g / mol; the content of plasticizing hydrocarbon resin is in a range from 30 to 100 pce; the resin-extended elastomer obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon resin in the liquid state; and preferably, for which at least one of the following characteristics is respected: the synthetic diene elastomer comprises at least one conjugated diene monomer having from 4 to 12 carbon atoms. the conjugated diene monomer having from 4 to 12 carbon atoms is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C 1 -C 5 alkyl)-1,3-butadienes, 1,3-pentadiene, 2,4-hexadiene and mixtures of these monomers. the conjugated diene monomer having from 4 to 12 carbon atoms is selected from the group consisting of 1,3-butadiene, 2-methyl-1,3-butadiene and mixtures of these monomers. the synthetic diene elastomer further comprises at least one vinylaromatic monomer having from 8 to 20 carbon atoms.the vinylaromatic monomer having from 8 to 20 carbon atoms is selected from the group consisting of styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, the commercial mixture "vinyl-toluene", para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene and mixtures of these monomers. the vinylaromatic monomer having from 8 to 20 carbon atoms is styrene and the conjugated diene monomer having 4 to 12 carbon atoms is 1,3-butadiene. the synthetic diene elastomer is functionalized by a function selected from the group consisting of functional groups comprising a carbon-tin bond, amine functional groups, functional groups comprising a silanol, functional groups comprising an alkoxysilane, carboxylic groups, polyether groups, epoxide groups and mixtures thereof.The synthetic diene elastomer is obtained by solution polymerization, preferably by homogeneous solution polymerization. The plasticizing hydrocarbon resin has a number-average molar mass of between 400 and 2000 g / mol, preferably between 500 and 1500 g / mol. The plasticizing hydrocarbon resin is selected from the group consisting of aliphatic resins, aromatic resins and mixtures of these resins.the plasticizing hydrocarbon resin is selected from the group consisting of cyclopentadiene homopolymer or copolymer resins, dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5-cut homopolymer or copolymer resins, C9-cut homopolymer or copolymer resins, blends of C5-cut homopolymer or copolymer resins and C9-cut homopolymer or copolymer resins, alpha-methyl-styrene homopolymer or copolymer resins and blends of these resins. the plasticizing hydrocarbon resin content is within a range of 30 to 80 pce.

[0179] The rubber compositions of the invention comprise at least one reinforcing filler.

[0180] Any type of reinforcing filler known for its ability to reinforce a rubber composition suitable for the manufacture of tires can be used, for example an organic filler, a reinforcing inorganic filler or a blend of these two types of filler.

[0181] As organic filler, mention may in particular be made of carbon blacks, functionalized polyvinyl organic fillers as described in applications WO2006 / 069792, WO2006 / 069793, WO 2008 / 003434 and WO2008 / 003435.

[0182] All carbon blacks are suitable as carbon blacks, in particular HAF, ISAF, SAF type blacks conventionally used in tires (so-called tire grade blacks). Among the latter, we will mention more particularly the reinforcing carbon blacks of the 100, 200 or 300 series (ASTM grades), such as for example blacks N115, N134, N234, N326, N330, N339, N347, N375, or even, depending on the intended applications, blacks of higher series (for example N660, N683, N772). The carbon blacks could for example already be incorporated into an elastomer, in particular isoprene, in the form of a masterbatch (see for example applications WO 97 / 36724 or WO 99 / 16600).

[0183] By "reinforcing inorganic filler" is meant in the present application, by definition, any inorganic or mineral filler (whatever its color and its natural or synthetic origin), also called "white" filler, "clear" filler or even "non-black filler" as opposed to carbon black, capable of reinforcing on its own, without any other means than an intermediate coupling agent, a rubber composition intended for the manufacture of tires, in other words capable of replacing, in its reinforcing function, a conventional tire-grade carbon black; such a filler is generally characterized, in a known manner, by the presence of hydroxyl groups (-OH) on its surface.

[0184] The physical state in which the reinforcing inorganic filler is presented is indifferent, whether in the form of powder, microbeads, granules, beads or any other suitable densified form.

[0185] Of course, the term reinforcing inorganic filler also means mixtures of different reinforcing inorganic fillers, in particular highly dispersible siliceous and / or aluminous fillers as described below.

[0186] Suitable reinforcing inorganic fillers are, in particular, mineral fillers of the siliceous type, in particular silica (SiO 2 ), or of the aluminous type, in particular alumina (Al 2 O 3 ). The silica used may be any reinforcing silica known to those skilled in the art, in particular any precipitated or pyrogenic silica having a BET specific surface area and a CTAB specific surface area both of less than 450 m 2 < / g, preferably from 30 to 400 m 2 < / g, the BET specific surface area and the CTAB specific surface area being measured as indicated above.In particular, so-called highly dispersible silicas (called “HDS”) may be used, such as, for example, Ultrasil 7000 silicas from the company Evonik, Zeosil ®< 1165 MP and Zeosil ®< 1115 MP silicas from the company Solvay, Zeosil ®< Premium 200MP silica from the company Solvay, Hi-Sil EZ150G silica from the company PPG, Zeopol 8715, 8745 or 8755 silicas from the company Huber, silicas as described in applications WO03 / 016215 and WO03 / 016387.

[0187] Of course, reinforcing inorganic filler also means mixtures of different reinforcing fillers, in particular highly dispersible siliceous fillers as described above.

[0188] Preferably, the total reinforcing filler content (carbon black and / or other reinforcing filler such as silica) is within a range from 10 to 200 phr, more preferably from 30 to 180 phr, more preferably from 50 to 160 phr, the optimum being known to be different depending on the particular applications targeted.

[0189] According to a variant of the invention, the reinforcing filler is predominantly other than carbon black, that is to say that it comprises more than 50% by weight of the total weight of the reinforcing filler, of one or more reinforcing fillers other than carbon black, in particular a reinforcing inorganic filler such as silica, or even it is exclusively composed of such a filler.

[0190] According to this variant, when black is also present, it may be used at a rate of less than 20 pce, more preferably less than 10 pce. For example, in this variant, the carbon black rate may be in a range from 0.5 to 20 pce, preferably in a range from 1 to 10 pce.

[0191] According to another variant of the invention, a reinforcing filler is used comprising mainly carbon black, and optionally silica or another inorganic reinforcing filler.

[0192] When the reinforcing filler comprises a filler requiring the use of a coupling agent to establish a bond between the reinforcing filler and the elastomer, the rubber compositions in accordance with the invention also comprise, in a conventional manner, a coupling agent capable of effectively ensuring this bond. For example, when silica is present in the composition as an inorganic reinforcing filler, organosilanes, in particular polysulfurized alkoxysilanes or mercaptosilanes, or at least bifunctional polyorganosiloxanes, may be used as coupling agents. For example, the agent for coupling the filler with the elastomer may be bis(3-triethoxysilylpropyl) tetrasulfide (abbreviated as TESPT).

[0193] Such a coupling agent should not be confused with the coupling agents used for the synthesis of the synthetic diene elastomer used as a basic constituent to form the resin-extended elastomer.

[0194] In the compositions according to the invention, the level of coupling agent is advantageously less than 20 phr, it being understood that it is generally desirable to use as little as possible. Its level is preferably within a range from 0.5 to 12 phr. The presence of the coupling agent depends on that of the reinforcing inorganic filler. The level of coupling agent of the inorganic reinforcing filler with the elastomer is easily adjusted by a person skilled in the art according to the level of this filler; it is typically of the order of 0.5% to 15% by weight relative to the weight of the reinforcing inorganic filler other than carbon black.

[0195] The rubber compositions according to the invention may further comprise at least one crosslinking system based either on sulfur, or on sulfur donors and / or peroxide and / or bismaleimides, vulcanization accelerators, vulcanization activators.

[0196] Preferably, the crosslinking system is preferably a vulcanization system, i.e. a system based on sulfur (or a sulfur-donating agent) and a primary vulcanization accelerator. To this basic vulcanization system may be added, incorporated during the first non-productive phase and / or during the productive phase as described later, various known secondary accelerators or vulcanization activators such as zinc oxide, stearic acid or equivalent compounds, guanidine derivatives (in particular diphenylguanidine), or even known vulcanization retarders.

[0197] When sulfur is used, it is used at a preferential rate in the range of 0.5 to 12 pce, in particular 1 to 10 pce. The primary vulcanization accelerator may be used at a preferential rate in the range of 0.5 to 10 pce, more preferably in the range of 0.5 to 5.0 pce.

[0198] Any compound capable of acting as a vulcanization accelerator for diene elastomers in the presence of sulfur may be used as an accelerator (primary or secondary), in particular accelerators of the thiazole type and their derivatives, accelerators of the thiuram type, zinc dithiocarbamates. These accelerators are, for example, chosen from the group consisting of 2-mercaptobenzothiazyl disulfide (abbreviated as "MBTS"), tetrabenzylthiuram disulfide ("TBZTD"), N-cyclohexyl-2-benzothiazyl sulfenamide ("CBS"), N,N-dicyclohexyl-2-benzothiazyl sulfenamide ("DCBS"), N-tert-butyl-2-benzothiazyl sulfenamide ("TBBS"), N-tert-butyl-2-benzothiazyl sulfenimide ("TBSI"), zinc dibenzyldithiocarbamate ("ZBEC") and mixtures of these compounds.

[0199] The rubber compositions in accordance with the invention as described above alone make it possible to respond to the technical problem posed, in particular they stick little to the mixing tools.

[0200] However, the rubber compositions according to the invention may also contain, in addition to the agents for coupling the inorganic reinforcing filler with the elastomer, coupling activators, filler recovery agents or more generally processing aids capable, in a known manner, thanks to an improvement in the dispersion of the filler in the composition and a reduction in the viscosity of the compositions, of improving its processability in the raw state, these agents being, for example, hydrolyzable silanes, such as alkylakoxysilanes, polyols, polyethers, primary, secondary or tertiary amines, hydroxylated or hydrolyzable polyorganosiloxanes.

[0201] Preferably, the rubber composition in accordance with the invention may comprise, in addition to the plasticizing hydrocarbon resin already present in the elastomer extended with the resin, another plasticizing hydrocarbon resin identical to or different from that present in the elastomer (additional resin).

[0202] Preferably, the total level of plasticizing resin (resin present in the elastomer extended to the resin and optionally additional resin) in the rubber composition according to the invention is within a range from 5 to 100 phr, preferably from 30 to 90 phr. Those skilled in the art know how to achieve this total level of plasticizing resin in the rubber compositions.

[0203] The rubber compositions in accordance with the invention may also comprise all or part of the usual additives normally used in elastomer compositions intended for the manufacture of tires, such as for example pigments, non-reinforcing fillers, protective agents such as antiozonating waxes, chemical antiozonants, antioxidants, anti-fatigue agents, plasticizing agents, methylene acceptors or donors (for example HMT or H3M) as described for example in application WO02 / 10269, a crosslinking system. Process for obtaining the composition

[0204] The rubber compositions in accordance with the invention may be manufactured in suitable mixers, using two successive preparation phases according to a general procedure well known to those skilled in the art: a first thermomechanical working or kneading phase (sometimes referred to as the “non-productive” phase) at high temperature, up to a maximum temperature of between 110°C and 190°C, preferably between 130°C and 180°C, followed by a second mechanical working phase (sometimes referred to as the “productive” phase) at a lower temperature, typically below 110°C, for example between 40°C and 100°C, a finishing phase during which the crosslinking system (preferably the vulcanization system) is incorporated.

[0205] Thus, the present description describes a process for preparing a composition according to the invention which comprises: (i) carrying out, at a maximum temperature between 130°C and 180°C, a first thermomechanical working time of the constituents of the composition which comprise at least one reinforcing filler and at least one elastomer extended to the resin as defined above, with the exception of a crosslinking system; (ii) carrying out, at a temperature lower than said maximum temperature of said first time, a second mechanical working time during which said crosslinking system is incorporated.

[0206] This process may also comprise, prior to carrying out the aforementioned steps (i) and (ii), the steps of the process for obtaining said resin-extended elastomer according to the process described above.

[0207] More specifically, the first phase (non-productive, step (i)) is preferably carried out in several thermomechanical steps. During a first step, the resin-extended elastomer(s), the reinforcing filler(s), possibly the plasticizers (including the addition of additional plasticizing resin and possibly the coupling agents and / or other ingredients) with the exception of the vulcanization system, are introduced into a suitable mixer such as a conventional internal mixer, at a temperature between 20°C and 100°C and, preferably, between 25°C and 100°C. After a few minutes, preferably 0.5 to 2 min and a rise in temperature to 90°C to 100°C, the other ingredients (i.e. those remaining if not all were added at the start) are added all at once or in parts, with the exception of the vulcanization system during mixing lasting from 20 seconds to a few minutes.The total duration of mixing, in this non-productive phase, is preferably between 2 and 10 minutes at a temperature less than or equal to 180°C, and preferably less than or equal to 170°C.

[0208] After cooling the mixture thus obtained, the crosslinking system (preferably the vulcanization system) is then incorporated at low temperature (typically below 100°C), generally in an external mixer such as a cylinder mixer; the whole is then mixed (productive phase, step (ii)) for a few minutes, for example between 5 and 15 min.

[0209] The final composition thus obtained is then calendered, for example in the form of a sheet or a plate, in particular for characterization in the laboratory, or extruded, to form for example a rubber profile used for the manufacture of semi-finished products in order to obtain products such as a tread. These products can then be used for the manufacture of tires, according to techniques known to those skilled in the art, namely by superimposing the layers of semi-finished products on top of each other before curing the tire

[0210] Crosslinking (or curing or vulcanization) is carried out in a known manner at a temperature generally between 130°C and 200°C, under pressure, for a sufficient time which can vary for example between 5 and 90 min depending in particular on the curing temperature, the vulcanization system adopted, the vulcanization kinetics of the composition considered or the size of the tire. 2.4 - Semi-finished product and tire

[0211] The invention also relates to a semi-finished product for a tire comprising at least one resin-extended elastomer as described above, including its preferred embodiments, or capable of being obtained according to the process described above, including its preferred embodiments.

[0212] The invention also relates to a semi-finished product for a tire comprising at least one rubber composition as described above, including its preferred embodiments.

[0213] Due to the viscosity of the resin-extended elastomer which is favorable for good processability of the rubber compositions containing it, it will be noted that these compositions can be used in any semi-finished tire product well known to those skilled in the art such as, for example, a tread.

[0214] The invention also relates to a tire comprising at least one resin-extended elastomer as described above, including its preferred embodiments, or capable of being obtained according to the method described above, including its preferred embodiments.

[0215] The invention also relates to a tire comprising at least one composition as described above.

[0216] The tire of the invention may be intended in particular to equip vehicles. These vehicles may be passenger-type motor vehicles, SUVs (“ Sports Utility Vehicles»), two-wheelers (particularly motorcycles), aircraft, as well as industrial vehicles chosen from vans, “Heavy Goods Vehicles” - i.e. metro, buses, road transport vehicles (trucks, tractors, trailers), off-road vehicles such as agricultural or civil engineering vehicles -, other transport or handling vehicles. 3 - EXAMPLES

[0217] The following examples illustrate the invention without, however, limiting it. 3.1 - Test 1 :

[0218] The purpose of this test is to demonstrate the improved processability properties of a resin-extended elastomer compared to a control extended elastomer and non-extended elastomers. 3.1.1 - Synthesis of the elastomers studied

[0219] Two non-resin-extended elastomers and two resin-extended elastomers were synthesized according to the protocols described below. The glass transition temperature of the starting elastomers, the starting plasticizing resins, and the glass transition temperature of the resin-extended elastomers were measured according to the method described in Section 1.3. The number-average molar masses of the elastomer and the plasticizing resin were measured according to the method described in Sections 1.1 and 1.2, respectively. The viscosities were measured according to the method described in Section 1.6. The plasticizing resin content in the resin-extended elastomers was measured according to the method described in Section 1.5. Elastomer A (outside the invention)

[0220] Into an 85-liter reactor, maintained under a nitrogen pressure of 2 bars, containing 48.4 kg of methylcyclohexane, 5.5 kg of butadiene and 1.7 kg of styrene are injected, as well as 525 ppm (678 mL) of tetrahydrofuran (THF). After neutralizing the impurities in the solution to be polymerized by adding n-butyllithium, 1.162 L of n-butyllithium at 0.014 mol / L are added. The reaction medium then takes on a yellow color. The polymerization is carried out at 50 °C. After 45 minutes, the monomer conversion rate reaches 68%. This rate is determined by weighing a dry extract at 140 °C, under the reduced pressure of 200 mm Hg.

[0221] The polymer chains are then functionalized by adding hexamethylcyclotrisiloxane to the reactor at a rate of 0.4 molar equivalents relative to the lithium chain end. Functionalization is carried out at 60°C for 30 minutes.

[0222] The polymer chains are neutralized by adding 0.9 parts per hundred parts of elastomers (pce) of 4,4'-methylene-bis-2,6-tert-butylphenol and 0.2 parts per hundred parts of elastomers (pce) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine. At the end of the neutralization step, a homogeneous solution of functionalized styrene-butadiene copolymer in the organic solvent is obtained.

[0223] The functionalized elastomer is separated from its solution by a steam stripping operation to recover a dispersion of elastomer particles in an aqueous solution. This dispersion is dried on cylinder tools at 100°C for 15 minutes.

[0224] At the end of the drying stage, elastomer A is recovered, the characteristics of which are presented in Table I. Elastomer B (excluding invention)

[0225] Into an 85-liter reactor, maintained under a nitrogen pressure of 2 bars, containing 48.4 kg of methylcyclohexane, 5.5 kg of butadiene and 1.7 kg of styrene are injected, as well as 525 ppm (678 mL) of THF. After neutralizing the impurities in the solution to be polymerized by adding n-butyllithium, 1.162 L of n-butyllithium at 0.014 mol / L are added. The reaction medium then takes on a yellow color. The polymerization is carried out at 50 °C. After 45 minutes, the monomer conversion rate reaches 68%. This rate is determined by weighing a dry extract at 140 °C, under the reduced pressure of 200 mm Hg.

[0226] The polymer chains are then functionalized by adding hexamethylcyclotrisiloxane to the reactor at a rate of 0.4 molar equivalents relative to the lithium chain end. Functionalization is carried out at 60°C for 30 minutes.

[0227] The polymer chains are neutralized by adding 0.9 parts per hundred parts of elastomers (pce) of 4,4'-methylene-bis-2,6-tert-butylphenol and 0.2 parts per hundred parts of elastomers (pce) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine. At the end of the neutralization step, a homogeneous solution of functionalized styrene-butadiene copolymer in the organic solvent is obtained.

[0228] The copolymer solution in methylcyclohexane is then transferred to a 450 liter reactor and stirred for 15 minutes. A solution of 2.34 kg of “Escorez 2173” resin dissolved in 4 liters of methylcyclohexane is then added to the copolymer solution. The copolymer and resin solution is stirred for two hours at room temperature under a nitrogen pressure of 0.4 bar with a stirring speed of 400 rpm. This gives a homogeneous solution of functionalized styrene butadiene copolymer and resin in a solvent.

[0229] This homogeneous solution of functionalized styrene-butadiene copolymer and resin is then subjected to a steam stripping operation in order to recover a dispersion of elastomer / resin particles in an aqueous solution. This dispersion is dried on cylinder tools at 100°C for 15 minutes.

[0230] At the end of the drying stage, the elastomer B extended with the resin is recovered, the characteristics of which are presented in Table I.

[0231] The plasticizing hydrocarbon resin is commercially available from Exxon Mobil under the reference “Escorez 2173”. Its characteristics are as follows: number-average molar mass of approximately 770 g / mol, plasticizing resin from a C5-C9 hydrocarbon fraction, glass transition temperature of approximately 39.7°C (Δ T: 13°C), softening temperature of approximately 94°C. Elastomer C (outside the invention)

[0232] Into an 85-liter reactor, maintained under a nitrogen pressure of 2 bars, containing 48.963 kg of methylcyclohexane, 5.23 kg of butadiene and 1.65 kg of styrene are injected, as well as 525 ppm (682 mL) of THF. After neutralizing the impurities in the solution to be polymerized by adding n-butyllithium, 796 mL of n-butyllithium at 0.014 mol / L are added. The reaction medium then takes on a yellow color. The polymerization is carried out at 50 °C. After 60 minutes, the monomer conversion rate reaches 66.5%. The conversion rate is determined by weighing a dry extract at 140 °C, under the reduced pressure of 200 mm Hg.

[0233] The polymer chains are then functionalized by adding hexamethylcyclotrisiloxane to the reactor at a rate of 0.4 molar equivalents relative to the lithium chain end. Functionalization is carried out at 60°C for 30 minutes.

[0234] The polymer chains are neutralized by adding 0.9 parts per hundred parts of elastomers (pce) of 4,4'-methylene-bis-2,6-tert-butylphenol and 0.2 parts per hundred parts of elastomers (pce) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine. A homogeneous solution of functionalized styrene-butadiene copolymer in methylcyclohexane is obtained.

[0235] The elastomer is separated from its solution by a steam stripping operation in order to recover a dispersion of elastomer particles in an aqueous solution. This dispersion is dried on cylinder tools at 100°C for 15 minutes.

[0236] At the end of the drying stage, elastomer C is recovered, the characteristics of which are presented in Table I. Elastomer D (in accordance with the invention)

[0237] Into an 85-liter reactor, maintained under a nitrogen pressure of 2 bars, containing 48.963 kg of methylcyclohexane, 5.23 kg of butadiene and 1.65 kg of styrene are injected, as well as 525 ppm (682 mL) of THF. After neutralizing the impurities in the solution to be polymerized by adding n-butyllithium, 796 mL of n-butyllithium at 0.014 mol / L are added. The reaction medium then takes on a yellow color. The polymerization is carried out at 50 °C. After 60 minutes, the monomer conversion rate reaches 66.5%. The conversion rate is determined by weighing a dry extract at 140 °C, under the reduced pressure of 200 mm Hg.

[0238] The polymer chains are then functionalized by adding hexamethylcyclotrisiloxane to the reactor at a rate of 0.4 molar equivalents relative to the lithium chain end. Functionalization is carried out at 60°C for 30 minutes.

[0239] The polymer chains are neutralized by adding 0.9 parts per hundred parts of elastomers (pce) of 4,4'-methylene-bis-2,6-tert-butylphenol and 0.2 parts per hundred parts of elastomers (pce) of N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine. A homogeneous solution of functionalized styrene-butadiene copolymer in methylcyclohexane is obtained.

[0240] The copolymer solution in methylcyclohexane is then transferred to a 450 liter reactor and stirred for 15 minutes. A solution of 2.17 kg of “Escorez 2173” resin dissolved in 4 liters of methylcyclohexane is then added to the copolymer solution. The copolymer and resin solution is stirred for two hours at room temperature under a nitrogen pressure of 0.4 bar with a stirring speed of 400 rpm. This gives a homogeneous solution of functionalized styrene-butadiene copolymer and resin in the solvent.

[0241] This homogeneous solution of functionalized styrene-butadiene copolymer and resin is then subjected to a steam stripping operation in order to recover a dispersion of elastomer / resin particles in an aqueous solution. This dispersion is dried on cylinder tools at 100°C for 15 minutes.

[0242] At the end of the drying stage, an elastomer D is obtained, the characteristics of which are presented in Table I. Characteristics of different elastomers

[0243] Tableau I Elastomer A Elastomer B Elastomer C Elastomer D Average molar mass Mn (g / mol) 170600 170600 290000 290000 Polydispersity index Ip 1,12 1,12 1,14 1,14 Tg in °C - 65°C (ΔT= 6°C) - 51.7°C (ΔT= 14.8° C) - 65°C (ΔT= 6 °C) - 51°C (ΔT= 14°C) Microstructure Styrene content ( a< ) 15,1 % 15,1 % 14,9 % 14,9 % 1,2-vinyl butadiene rate ( b< ) 24,6 % 24,6 % 23,6 % 23,6 % Butadiene rate 1.4 ( b< ) 75,4 % 75,4 % 76,4 % 76,4% Plasticizing resin content (in parts per unit) 0 50 0 50 (a<): the monomer rate is expressed in % by weight relative to the total weight of the elastomer (b<): the monomer rate is expressed in % by weight relative to the weight of the polybutadiene part 3.1.2 - Results

[0244] The processability of these elastomers is evaluated by measuring their Mooney viscosity according to the method described in paragraph 1.6 and the results are presented in Table II. The Mooney viscosity is a parameter well known to those skilled in the art. It is generally accepted that the lower the Mooney viscosity of an elastomer, the more difficult it is to use this elastomer, particularly in mixtures. Furthermore, a Mooney viscosity of an elastomer greater than 100 UM is also not sought by formulators of rubber compositions. Table II Elastomer A (outside the invention) Elastomer B extended with resin (outside the invention) Elastomer C (outside the invention) Elastomer D extended with resin (in accordance with the invention) Mooney Viscosity (UM) 40 23 >100 71 1 UM = 0.83 Nm

[0245] Elastomer A (outside the invention) is representative of an elastomer conventionally used in rubber compositions, particularly for the manufacture of tires. It has a Mooney viscosity of 40 UM, representing a good ability of the elastomer to be processable because it is not very sticky.

[0246] When a plasticizing resin is mixed with this elastomer A to form resin-extended elastomer B (resin-extended elastomer not included in the invention), a decrease in Mooney viscosity to 23 UM is observed. This decrease in viscosity is not compatible with the use of this compound in a rubber composition. This compound is difficult to process because it is very sticky.

[0247] When the number-average molar mass of elastomer A is increased to obtain elastomer C (elastomer outside the invention), an increase in its viscosity is also observed, suggesting great difficulty in the processability of this elastomer.

[0248] Surprisingly, when a plasticizing resin is mixed with elastomer C, resin-extended elastomer D (resin-extended elastomer according to the invention) is obtained, which has a Mooney viscosity of 70 UM. The Mooney viscosity of resin-extended elastomer D is higher than that of elastomer A and assumes good processability. 3.2 - Test 2 :

[0249] The purpose of this test is to show the improved processability properties of a composition according to the invention (C1) comprising an elastomer extended with resin in accordance with the invention compared to a control composition (T1) comprising an elastomer of the same microstructure but not extended with resin. 3.2.1 - Formulation of compositions :

[0250] The formulations of compositions T1 and C1 are presented in Table III. The rates of the different constituents are expressed in pce. The results of the sticky properties measured on the raw (i.e. unvulcanized) compositions are presented in Table IV.

[0251] Composition C1 according to the invention differs from composition T1 by the nature of the elastomer: it comprises an elastomer extended with resin. Compositions C1 and T1 have the same total content of plasticizing resin (76 pce). Tableau III Composition T1 C1 Elastomer A (1) 100 (-) Elastomer D (2) (-) 150 Carbon black (3) 7 7 Silica (4) 145 145 Coupling agent (5) 10,9 10,9 TDAE Oil (6) 44 44 Plasticizing resin (7) 2 2 Plasticizing resin (8) 74 24 Antiozonant wax 1,5 1,5 Antioxidant (9) 2 2 Accelerator (10) 2,7 2,7 DPG (11) 2,2 2,2 Sulfur 1,8 1,8 Stearic acid 2 2 Zinc oxide 3 3 For this test, it was not possible to use elastomer C in a rubber composition because it has too high a Mooney viscosity. It is therefore difficult to process. (1) Elastomer A obtained according to the process described in paragraph 3.1.1. a) and whose characteristics are reported in Table I; (2) Elastomer D obtained according to the process described in paragraph 3.1.1.d) and whose characteristics are reported in Table I; (3) Carbon black grade N234 marketed by Cabot Corporation; (4) Silica: Zeosil ®< 1115MP silica marketed by Solvay, (5) Coupling agent: Bis[3-(triethoxysilyl)propyl] Tetrasulfide silane (TESPT) marketed by Evonik under the reference “Si69”; (6) TDAE oil: TDAE oil marketed by Klaus Dahleke under the reference 3VIVATEC500; (7) Plasticizing resin: resin marketed by Exxon Mobil under the reference “Escorez 1102”; (8) Plasticizing resin: resin marketed by Exxon Mobil under the reference “Escorez 2173”; (9) Antioxidant: N-1,3-dimethylbutyl-N-phenyl-para-phenylenediamine marketed by Flexys under the reference “Santoflex 6-PPD”; (10) Accelerator: N-cyclohexyl-2-benzothiazyl-sulfenamide marketed by Flexys under the reference “Santocure CBS”; (11) DPG: diphenylguanidine marketed by Flexys under the reference “Perkacit”. 3.2.2 - Obtaining the compositions :

[0252] The compositions are prepared according to the following protocol:

[0253] The elastomers, whether or not extended with resin, the reinforcing filler (silica), the carbon black, the coupling agent, and then, after one to two minutes of mixing, the various other ingredients, with the exception of the vulcanization system, are introduced into an internal mixer, filled to 70% and with an initial tank temperature of approximately 50°C. Thermomechanical work (non-productive phase) is then carried out in one step (total mixing time approximately 5 min), until a maximum "drop" temperature of approximately 165°C is reached.

[0254] The resulting mixture is recovered, cooled and then the vulcanization system (sulfur and accelerator) is added to an external mixer (homo-finisher) at 70°C, mixing everything (productive phase) for approximately 5 to 6 minutes.

[0255] The compositions thus obtained are then calendered in the form of plates (thickness of 2 to 3 mm) for the measurement of their physical or mechanical properties before cooking. 3.2.3 - Results :

[0256] The tack properties of compositions T1 and C1 are measured according to the method described in paragraph 1.7 and presented in the following table IV. Table IV Composition T1 Composition C1 Sticky 100 36

[0257] Table IV shows that composition C1 comprising an elastomer extended with the resin in accordance with the present invention has significantly lower tack properties than composition T1 representative of a rubber composition intended for the manufacture of tires. This result is all the more surprising since compositions C1 and T1 have the same total content of plasticizing resin, namely 76 pce.

Claims

1. Resin-extended elastomer, the elastomer of which is a synthetic diene elastomer with a number-average molar mass in a range extending from 250 000 g / mol to 450 000 g / mol and the resin of which is a plasticizing hydrocarbon-based resin, and the content of plasticizing hydrocarbon-based resin is in a range extending from 30 to 100 phr, the resin-extended elastomer being obtained by mixing the synthetic diene elastomer in solution in an organic solvent and the plasticizing hydrocarbon-based resin in the liquid state and the resin-extended elastomer having a Mooney viscosity index of greater than or equal to 40 MU .

2. Resin-extended elastomer according to Claim 1, in which the synthetic diene elastomer is functionalized with a function chosen from the group constituted by functional groups including a carbon-tin bond, amino functional groups, functional groups including a silanol, functional groups including an alkoxysilane, carboxyl groups, polyether groups, epoxide groups and mixtures thereof.

3. Resin-extended elastomer according to any one of Claims 1 to 2, in which the synthetic diene elastomer is obtained by solution polymerization, preferably by homogeneous solution polymerization.

4. Resin-extended elastomer according to any one of Claims 1 to 3, in which the plasticizing hydrocarbon-based resin is chosen from the group constituted by aliphatic resins, aromatic resins and mixtures of these resins.

5. Resin-extended elastomer according to Claim 4, in which the plasticizing hydrocarbon-based resin is chosen from the group constituted by cyclopentadiene homopolymer or copolymer resins, dicyclopentadiene homopolymer or copolymer resins, terpene homopolymer or copolymer resins, C5 fraction homopolymer or copolymer resins, C9 fraction homopolymer or copolymer resins, mixtures of C5 fraction homopolymer or copolymer resins and of C9 fraction homopolymer or copolymer resins, α-methylstyrene homopolymer or copolymer resins, and mixtures of these resins.

6. Resin-extended elastomer according to any one of Claims 1 to 5, in which the content of plasticizing hydrocarbon-based resin is in a range extending from 30 to 80 phr.

7. Process for obtaining a resin-extended elastomer according to any one of Claims 1 to 6, the process comprising at least: (a) one step of placing at least one synthetic diene elastomer in solution in an organic solvent in contact with at least one plasticizing hydrocarbon-based resin in the liquid state, said synthetic diene elastomer having a number-average molar mass in a range extending from 250 000 g / mol to 450 000 g / mol, (b) one mixing step to obtain a homogeneous solution of synthetic diene elastomer and of plasticizing hydrocarbon-based resin, (c) one steam stripping step to recover a gaseous fraction enriched in organic solvent and an aqueous dispersion of particles of synthetic diene elastomer and of plasticizing hydrocarbon-based resin; and (d) one step of recovering the resin-extended elastomer from the aqueous dispersion of particles of synthetic diene elastomer and of plasticizing hydrocarbon-based resin.

8. Process for obtaining a resin-extended elastomer according to Claim 7, in which the synthetic diene elastomer of step (a) is obtained either by dissolution of said elastomer in the organic solvent or by solution polymerization in the organic solvent of the corresponding monomers of said elastomer.

9. Process for obtaining a resin-extended elastomer according to Claim 7 or 8, in which the plasticizing hydrocarbon-based resin in the liquid state is obtained by heating said resin to a temperature greater than or equal to its softening point.

10. Process for obtaining a resin-extended elastomer according to Claim 7 or 8, in which the plasticizing hydrocarbon-based resin in the liquid state is obtained by dissolving said resin in an organic solvent identical to or different from the organic solvent in which the synthetic diene elastomer is present.

11. Composition based on at least one resin-extended elastomer as defined according to any one of Claims 1 to 6 or obtained according to the process either of Claims 7 to 10, on at least one reinforcing filler and on at least one chemical crosslinking system.

12. Semi-finished product for a tyre, comprising at least one composition as defined in Claim 11.

13. Tyre comprising at least one composition as defined in Claim 11.